[Radiance-general] 5-phase method model reflectance

[Eleonora Brembilla]

Dear All

I am doing some analyses on reflectance values and I have just started using the 5-phase method for those.

At first I thought the reflectances assigned to the model would not matter for the part that is specific to the 5-phase, as the model is assigned a black material, but comparing the resulting matrices it looks like the Sun Coefficient Matrix (.dsc) changes with the original materials’ reflectances (and it’s the only matrix that change). And that is exactly the matrix that is taking most of the computational effort (about 4 hours I think - the same model with the 2-phase method takes 5 minutes, glazing is all simple clear glass).

5pm_dsc.opt:     -ab 1 -ad 50000 -as 0 -lw 2e-5 -dc 1 -dt 0 -dj 1 -st 1 -ss 0

rfluxmtx -n 4 -faa -I+ @5pm_dsc.opt -y `wc -l < $prj.pts` < $prj.pts - skies/suns.rad $pmats/materials-$i.rad $prj-black.rad windows.rad > dmx/MF6.dsc
oconv $pmats/materials-$i.rad $prj-black.rad windows.rad skies/suns.rad > octs/model_suns-$i.oct
rcontrib -n 4 -I+ @5pm_dsc.opt -faa -e MF:6 -f reinhart.cal -b rbin -bn Nrbins -o dmx/MF6-$i.dsc -m solar octs/model_suns-$i.oct < $prj.pts

Am I doing something wrong or is this the normal behaviour? The data I get in the end are plausible. Could you explain why the Sun Coefficient Matrix needs to take into account the model reflectances at all?

I hope I managed to explain the issue somehow... Thanks for your help!

Eleonora
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